Proppant particulates formed from polyaromatic hydrocarbons

ABSTRACT

Proppant particulates are commonly used in hydraulic fracturing operations to maintain one or more fractures in an opened state following the release of hydraulic pressure. In complex fracture networks, it can be difficult to deposit proppant particulates fully within the fractures. In addition, low crush strengths may result in problematic fines formation. Polyaromatic hydrocarbons, commonly encountered in various refinery process streams, may serve as an advantageous precursor to proppant particulates. Polyaromatic hydrocarbons may undergo crosslinking under acid-catalyzed conditions in an aqueous solvent in the presence of a surfactant to form substantially spherical particulates that may serve as effective proppant particulates during fracturing operations. In situ formation of the proppant particulates may take place in some cases.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit to U.S. Provisional Application Ser.No. 62/784,886, filed Dec. 26, 2018, the disclosure of which is hereinincorporated by reference in its entirety.

FIELD

The present disclosure relates to fracturing operations and proppantparticulates employed therein.

BACKGROUND

A wellbore may be drilled into a subterranean formation in order topromote removal (production) of a hydrocarbon resource therefrom. Inmany cases, the subterranean formation needs to be stimulated in somemanner in order to promote more effective removal of the hydrocarbonresource. Stimulation operations may include any operation performedupon the matrix of a subterranean formation in order to improve fluidconductivity therethrough.

Stimulation operations may include processes such as acidizing,fracturing, or a combination thereof. Acidizing operations dissolve aportion of the matrix of a subterranean formation to promote moreeffective fluid flow therethrough. Fracturing operations, in contrast,pump large quantities of fluid into a subterranean formation under highhydraulic pressure to promote formation of a plurality of fractures(channels) within the matrix of the subterranean formation to create ahigh-conductivity flow path, Both primary fractures extending from thewellbore and secondary fractures extending from the primary fractures,possibly dendritically, may be formed during a fracturing operation.

Proppant particulates are often included in a fracturing fluid in orderto keep the fractures open after the hydraulic pressure has beenreleased following a fracturing operation. Highly viscous fluids, oftenemploying a polymer gel, may be employed to promote effective transportof the proppant particulates. Upon reaching the fractures, the proppantparticulates settle therein, thereby preventing the fractures fromdosing once the hydraulic pressure has been released.

There are oftentimes difficulties encountered during fracturingoperations, particularly associated with deposition of proppantparticulates in fractures that have been created or extended underhydraulic pressure. Because proppant particulates are often fairly densematerials, effective transport of the proppant particulates may bedifficult, even when employing gelled fracturing fluids. Even aided by agelled fracturing fluid, it can still be difficult to distributeproppant particulates into the more remote reaches of a network offractures. In addition, fines produced from crushing of proppantparticulates within a wellbore can also lessen fluid conductivity, whichmay decrease production rates and/or necessitate wellbore cleanoutoperations. Moreover, the polymer gels commonly used to promoteeffective transport of proppant particulates may not completely breakfollowing a fracturing operation, which may lead to formation damage anddecreased hydrocarbon resource production.

SUMMARY

In some embodiments, the present disclosure provides solid compositionsthat may be used as proppant particulates. The solid compositionscomprise: a crosslinked reaction product of a polyaromatic hydrocarbonand a crosslinking agent. The crosslinking agent comprises at least twofunctional groups that are reactive under acid-catalyzed conditions withan aromatic ring of to the polyaromatic hydrocarbon. The crosslinkedreaction product is formed as substantially spherical particulates.

In other embodiments, the present disclosure provides methods for makingsubstantially spherical particulates from a polyaromatic hydrocarbon.The methods comprise: reacting a polyaromatic hydrocarbon with acrosslinking agent in the presence of an acid catalyst and a surfactantin an aqueous solvent, and forming substantially spherical particulatesin situ in the aqueous solvent. The substantially spherical particulatescomprise a crosslinked reaction product of the polyaromatic hydrocarbonand the crosslinking agent.

In still other embodiments, the present disclosure provides methods forfracturing a subterranean formation. The fracturing methods comprise:providing a plurality of proppant particulates comprising a crosslinkedreaction product of a polyaromatic hydrocarbon and a crosslinking agent,the crosslinked reaction product being formed as substantially sphericalparticulates; introducing a fracturing fluid comprising the plurality ofproppant particulates into a subterranean formation; and depositing atleast a portion of the plurality of proppant particulates within one ormore fractures in the subterranean formation.

BRIEF DESCRIPTION OF THE DRAWINGS

Not applicable.

DETAILED DESCRIPTION

The present disclosure generally relates to fracturing and, morespecifically, to proppant particulates for fracturing that are formedfrom various polyaromatic hydrocarbon sources.

As discussed above, proppant particulates can be used effectively duringfracturing operations, but there may be issues associated with theiruse. First, the high densities of many common proppant particulates mayhinder particulate transport, possibly leading to inadequate proppantdisposition within a plurality of fractures. Second, some proppantparticulates are prone to fines formation due to low crush strengthvalues, which may lead to decreased fracture conductivity due to finesaccumulation within a wellbore. Finally, polymeric gels used to promotetransport of proppant particulates can themselves be problematic if theyare not effectively removed from the fractures within a wellbore.Low-density proppant particulates may address the foregoingdifficulties, at least in part, but they are oftentimes rather high incost.

The present disclosure alleviates the foregoing difficulties andprovides related advantages as well. In particular, the presentdisclosure provides proppant particulates that may exhibit low densitiesand high crush strengths, thereby addressing two significantshortcomings of traditional proppant particulates, such as sand andceramics. The low density values may decrease or eliminate the need toutilize a gelled polymer to promote effective transport of the proppantparticulates. Moreover, the proppant particulates disclosed herein maybe formed readily from various low-cost polyaromatic hydrocarbonsources, such as those produced from various refinery process streamshaving high aromaticity that may otherwise have rather low intrinsicvalue. Illustrative polyaromatic hydrocarbon sources that may besuitable for use in the disclosure herein may have an aromatic contentabove about 60%. In more specific examples, polyaromatic hydrocarbonsources suitable for use in the disclosure herein may have an aromaticcontent about 80% or above and a ratio of carbon to hydrogen of about1.4:1 or lower.

The proppant particulates described herein may be prepared by reacting apolyaromatic hydrocarbon with a crosslinking agent comprising at leasttwo reactive functional groups. The at least two reactive functionalgroups convey bifunctional reactivity upon a linker bridging a firstpolyaromatic hydrocarbon molecule to at least a second polyaromatichydrocarbon molecule. The crosslinking chemistries described herein areacid-catalyzed and are believed to proceed through a carbocationintermediate in an electrophilic aromatic substitution reaction. Avariety of acid catalysts may be employed for this purpose.

The acid-catalyzed crosslinking of polyaromatic hydrocarbons accordingto the present disclosure takes place in the presence of a surfactant.The surfactant provides several advantageous and surprising benefits.First, the surfactant allows the crosslinking chemistry to take place inwater or other substantially aqueous solvents, in contrast to manytraditional electrophilic aromatic substitution reactions in which watertends to reduce the activity of the acid catalyst. At the very least,the use of water or other substantially aqueous solvents as a reactionmedium provides environmental advantages over syntheses employing onlyorganic solvents. Second, the surfactant may promote micellar dispersionof the polyaromatic hydrocarbon and the crosslinking agent in thesolvent. The micellar dispersion innately results in substantiallyspherical particle growth within the solvent up to a criticalparticulate size, at which point the surfactant is no longer able tomaintain the particulates in a dispersed state. Without being bound bytheory or mechanism, the substantially spherical particulate growth isbelieved to result from surface tension effects of the solvent upon thecrosslinked product as the molecular weight increases. Thus, the presentdisclosure allows proppant particulates having a relatively uniform sizedistribution to be obtained via a straightforward synthetic procedurewithout having to perform a post-synthesis sizing operation. Moreover,by varying the reactant or the surfactant concentrations and/or bychanging the surfactant itself, the size distribution of the proppantparticulates may be varied in response to particular application needs.The crosslinking density of the proppant particulates may likewise bevaried to change particulate hardness values in response to particularapplication needs.

Moreover, the ready formation of crosslinked polyaromatic hydrocarbonsaccording to the present disclosure may allow in situ formation ofproppant particulates to take place in a wellbore, according to someembodiments. In situ formation of proppant particulates may beparticularly desirable in subterranean formations in which proppantdelivery is otherwise difficult (e.g., tight formations having a smallfracture size and/or a complex fracture network pattern). In situformation of proppant particulates may likewise decrease or eliminatethe need to utilize a gelled polymer to promote effective transport ofthe proppant particulates.

All numerical values within the detailed description and the claimsherein are modified by “about” or “approximately” with respect to theindicated value, and take into account experimental error and variationsthat would be expected by a person having ordinary skill in the art.Unless otherwise indicated, room temperature is about 25° C.

As used in the present disclosure and claims, the singular forms “a,”“an,” and “the” include plural forms unless the context clearly dictatesotherwise.

The term “and/or” as used in a phrase such as “A and/or B” herein isintended to include “A and B,” “A or B,” “A”, and “B.”

For the purposes of the present disclosure, the new numbering scheme forgroups of the Periodic Table is used. In said numbering scheme, thegroups (columns) are numbered sequentially from left to right from 1through 18, excluding the f-block elements (lanthanides and actinides).

The term “hydrocarbon” refers to a class of compounds containinghydrogen bound to carbon, and encompasses (i) saturated hydrocarboncompounds, (ii) unsaturated hydrocarbon compounds, and (iii) mixtures ofhydrocarbon compounds (saturated and/or unsaturated), including mixturesof hydrocarbon compounds having different numbers of carbon atoms. Theterm “C_(n)” refers to hydrocarbon(s) or a hydrocarbyl group having ncarbon atom(s) per molecule or group, wherein n is a positive integer.Such hydrocarbon compounds may be one or more of linear, branched,cyclic, acyclic, saturated, unsaturated, aliphatic, or aromatic.

The terms “saturated” or “saturated hydrocarbon” refer to a hydrocarbonor hydrocarbyl group in which all carbon atoms are bonded to four otheratoms or are bonded to three other atoms with one unfilled valenceposition thereon.

The terms “unsaturated” or “unsaturated hydrocarbon” refer to ahydrocarbon or hydrocarbyl group in which one or more carbon atoms arebonded to less than four other atoms, optionally with one unfilledvalence position on the one or more carbon atoms. More specifically,unsaturated carbon atoms may possess at least one carbon-carbon doublebond and/or at least one carbon-carbon triple bond.

The terms “hydrocarbyl” and “hydrocarbyl group” are used interchangeablyherein. The term “hydrocarbyl group” refers to any C₁-C₁₀₀ hydrocarbongroup bearing at least one unfilled valence position when removed from aparent compound. “Hydrocarbyl groups” may be optionally substituted, inwhich the term “optionally substituted” refers to replacement of atleast one hydrogen atom or at least one carbon atom with a heteroatom orheteroatom functional group. Heteroatoms may include, but are notlimited to, B, O, N, S, P, F, Cl, Br, I, Si, Pb, Ge, Sn, As, Sb, Se, andTe. Heteroatom functional groups that may be present in substitutedhydrocarbyl groups include, but are not limited to, functional groupssuch as O, S, S═O, S(═O)₂, NO₂, F, Cl, Br, I, NR₂, OR, SeR, TeR, PR₂,AsR₂, SbR₂, SR, BR₂, SiR₃, GeR₃, SnR₃, PbR₃, where R is a hydrocarbylgroup or H. Suitable hydrocarbyl groups may include alkyl, alkenyl,alkynyl, aryl, aralkyl, heteroaryl, cycloalkyl, heterocyclyl, and thelike, any of which may be optionally substituted.

The term “alkyl” refers to a hydrocarbyl group having no unsaturatedcarbon-carbon bonds, and which may be optionally substituted. The term“alkylene” refers to an alkyl group having at least two open valencepositions.

The term “alkenyl” refers to a hydrocarbyl group having a carbon-carbondouble bond, and which may be optionally substituted. The terms “alkene”and “olefin” are used synonymously herein. Similarly, the terms“alkenic” and “olefinic” are used synonymously herein. Unless otherwisenoted, all possible geometric isomers are encompassed by these terms.The term “diene” refers to an alkenyl group having two carbon-carbondouble bonds.

The terms “aromatic” and “aromatic hydrocarbon” refer to a hydrocarbonor hydrocarbyl group having a cyclic arrangement of conjugatedpi-electrons that satisfy the Hückel rule. The term “aryl” is equivalentto the term “aromatic” as defined herein. The term “aryl” refers to botharomatic compounds and heteroaromatic compounds, either of which may beoptionally substituted. Both mononuclear and polynuclear aromatic andheteroaromatic compounds are encompassed by these terms. The term“arylene” refers to an aryl group having at least two open valencepositions.

Examples of saturated hydrocarbyl groups include, but are not limitedto, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, pentyl, isopentyl, hexyl, octyl, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cyclooctyl, and the like, including theirsubstituted analogues. Examples of unsaturated hydrocarbyl groupsinclude, but are not limited to, ethenyl, propenyl, allyl, butadienyl,cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cyclooctenyland the like, including their substituted analogues.

Examples of aromatic hydrocarbyl groups include, but are not limited to,phenyl, tolyl, xylyl, naphthyl, and the like, including all possibleisomeric forms thereof. Heteroaryl and polynuclear heteroaryl groups mayinclude, but are not limited to, pyridine, quinoline, isoquinoline,pyrimidine, quinazoline, acridine, pyrazine, quinoxaline, imidazole,benzimidazole, pyrazole, benzopyrazole, oxazole, benzoxazole, isoxazole,benzisoxazole, imidazoline, thiophene, benzothiophene, furan andbenzofuran. Polynuclear aryl hydrocarbyl groups may include, but are notlimited to, naphthalene, anthracene, indane, indene, and tetralin.

The term “polyaromatic hydrocarbon” refers to a hydrocarbyl groupbearing at least two aromatic rings, which may be fused or unfused.Optional heteroatom substitution may be present in at least one of theat least two aromatic rings.

The term “linear” refers to a hydrocarbon or hydrocarbyl group having acontinuous carbon chain without side chain branching, in which thecontinuous carbon chain may be optionally substituted with heteroatomsor heteroatom groups.

The terms “branch” and “branched” refer to a hydrocarbon or hydrocarbylgroup having a linear main carbon chain or cyclic carbon ring in which ahydrocarbyl side chain extends from the linear main carbon chain orcyclic carbon ring. Optional heteroatom substitution may be present inthe linear main carbon chain, the cyclic carbon ring, or in thehydrocarbyl side chain.

The term “benzylic” refers to a sp³ carbon atom directly bonded to anaromatic or heteroaromatic ring.

The term “allylic” refers to a sp³ carbon atom directly bonded to anolefinic carbon atom.

The present disclosure describes solid compositions that are acrosslinked reaction product of a polyaromatic hydrocarbon and acrosslinking agent. The crosslinking agent comprises at least twofunctional groups that are reactive under acid-catalyzed conditions withan aromatic ring of the polyaromatic hydrocarbon. The crosslinkedreaction product is formed as substantially spherical particulates.

In general, the solid compositions of the present disclosure featurecrosslinked reaction products having a substructure defined by Formula 1below,PAH1-L-PAH2  Formula 1wherein PAH1 and PAH2 are first and second polyaromatic hydrocarbons andL is a crosslinking group forming a bridge between PAH1 and PAH2. Thecrosslinking group is the entity resulting from a reaction between agiven polyaromatic hydrocarbon and a suitable crosslinking agent,examples of which are disclosed herein below. The entity definingcrosslinking group L may or may not comprise the entirety of a reactivefunctional group that undergoes a reaction with a polyaromatichydrocarbon. That is, some reactive functional groups may undergo areaction with a polyaromatic hydrocarbon directly without losing an atomto form a reactive species, whereas to other reactive functional groupsmay lose one or more atoms or be lost altogether when forming a reactivespecies to promote reactivity with a polyaromatic hydrocarbon. Forexample, alkyl and acyl halides may lose a halogen atom to form anelectrophile suitable for functionalizing an aromatic ring of apolyaromatic hydrocarbon according to some embodiments of the presentdisclosure.

Although not shown in Formula 1 above, PAH1 and/or PAH2 may be furthercrosslinked to additional polyaromatic hydrocarbons. Alternately or inaddition, multiple crosslinking groups may extend between PAH1 and PAH2and/or additional polyaromatic hydrocarbons, in some embodiments. Whenmultiple crosslinking groups are present, they may extend between thesame aromatic ring and/or different aromatic rings of each polyaromatichydrocarbon.

In some embodiments, suitable crosslinking agents may have a structureshown in Formula 2,

wherein J is a spacer group defining at least a portion of crosslinkinggroup L (Formula 1), FG1 is a first reactive functional group and(FG2)_(n) is at least a second reactive functional group, wherein n isan integer ranging from 1 to the number of open valence positions in J.For example, when J is an aromatic ring, n may vary up to the number ofopen valence positions (unsubstituted aromatic ring carbon atoms) in thearomatic ring. FG1 and FG2 may be the same or different in a givencrosslinking agent. Particular crosslinking agents shown below featureboth reactive functional groups as the same. Suitable crosslinkingagents may be chosen with reactive functional groups capable ofproducing an electrophile that may react with one or more aromatic ringsof a polyaromatic hydrocarbon. Examples of reactive functional groupsthat may be present in the crosslinking agents suitable for use in thepresent disclosure include, for example, alkenes (including styrenes andother vinyl aromatic compounds), aldehydes, benzylic halides, benzylicalcohols, benzylic sulfonates, acyl halides, carboxylic acids,carboxylic anhydrides, and the like.

In some more specific embodiments, crosslinking agents suitable for usein the present disclosure may have Formula 3 below, in which J is aphenyl ring and Q represents optional functionality that may be presentbut does not play a role in crosslinking to a polyaromatic hydrocarbon.

The reactive functional groups upon the aromatic ring may be the same ordifferent, and any substitution pattern of the reactive functionalgroups may be present. In particular embodiments, two of the same typeof reactive functional group may be present (i.e., FG1=FG2). Again, anyof the reactive functional groups discussed above may be present.Particular examples of aromatic crosslinking agents bearing suchreactive functional groups include, for example, the compoundsrepresented by Formula 4 below, wherein FG1 and FG2 are independentlyselected from —CHO, —CHCH₂, —CH₂X (X=halide, OH, or sulfonate), and —COY(Y=halide, OH or O-acyl).

Again, it is to be appreciated that FG1 and FG2 may be the same ordifferent. Although Formula 4 has shown a p-di-substituted aromaticring, it is to be appreciated that o- or m-di-substituted aromatic ringvariants may function similarly during crosslinking.

Other suitable crosslinking agents may be based upon a naphthalene orbiaryl scaffold, as shown in Formulas 5 and 6 below, wherein FG1, FG2and Q are defined as above and y₁ and y₂ are integers ranging from 0 upto the number of open valence positions in each corresponding aromaticring, provided that at least two reactive functional groups are presentin a given crosslinking agent (i.e., y₁+y₂≥2). That is, the reactivefunctional groups may be present upon the same or different aromaticrings in the crosslinking agents defined by Formulas 5 and 6.

Still other suitable crosslinking agents may be polymeric in nature.Exemplary polymeric crosslinking agents that may be used to promotecrosslinking of polyaromatic hydrocarbons according to the presentdisclosure are shown in Formulas 7 and 8 below, wherein FG may beselected from the reactive functional groups specified above.

In Formulas 7 and 8, M₁ is a first monomer unit and M₂ is a secondmonomer unit (mer unit), which may be the same or different. Variables rand s are 0 or a positive integer, provided that r+s≥1, and t is apositive integer ranging from 1 to about 1,000,000. Each reactivefunctional group in a polymeric crosslinking agent may be the same ordifferent. Particular examples of polymeric crosslinking agents that maybe suitable for use in the disclosure herein include, for example,poly(formylstyrene), poly(vinylstyrene), poly(halobenzylstyrene),poly(hydroxybenzyl)styrene, polyvinylchloride, and polybutadiene,including any homopolymer or copolymer thereof. Thus, although Formulas7 and 8 have been shown as copolymers, wherein one of the mer unitsbears the reactive functional groups, it is to be appreciated thathomopolymers bearing a reactive functional group upon each mer unit mayalso constitute suitable crosslinking agents in the embodiments of thepresent disclosure.

In still other embodiments, suitable crosslinking agents may includedicyclopentadiene or any alkylated variant thereof. According to thepresent disclosure, both double bonds in dicyclopentadiene (Formula 9)may be reacted with a polyaromatic hydrocarbon under acid-catalyzedconditions to form a crosslinked reaction product.

Accordingly, in some embodiments of the present disclosure, the at leasttwo functional groups in the crosslinking agents of the presentdisclosure may be located upon one or more aromatic rings of thecrosslinking agent. In more specific embodiments, the at least twofunctional groups may be independently selected from —CHO, —CHCH₂, —CH₂X(X=halide, OH, or sulfonate) and —C(═O)Y (Y═OH, Cl, and O-acyl). In someembodiments, the crosslinking agent may be a polymeric crosslinkingagent.

The solid compositions disclosed herein feature crosslinked reactionproducts that may be formed as substantially spherical particulates. Theterm “substantially spherical” refers to both true sphericalparticulates and ovular particulates, wherein ovular particulates mayhave a minor axis length differing from a major axis length by about 10%or less. Alternately, the assignment of a particulate as being“substantially spherical” may be determined from a Krumbien/Sloss chart,as specified in ISO13503-2:2006, wherein a substantially sphericalparticulate has x and y values on the Krumbien/Sloss chart that are bothgreater than or equal to 0.6. Irregular surface features, includingmicroscopic surface features not visible to the naked eye, uponparticulates that are otherwise substantially spherical also residewithin the scope of the present disclosure. Agglomerates ofsubstantially spherical particulates likewise reside within the scope ofthe present disclosure.

In more particular embodiments, substantially spherical particulates ofthe present disclosure may have a particle size ranging from about 10microns to about 3 mm or about 100 microns to about 1 mm. It is to beappreciated that the particle size may be varied in response toparticular application needs during production of the substantiallyspherical particulates. Methods for producing substantially sphericalparticulates from polyaromatic hydrocarbons are discussed in furtherdetail herein below.

In some or other embodiments, substantially spherical particulates ofthe present disclosure may have a density ranging from about 0.8 g/cm³to about 1.5 g/cm³ or from about 1.0 g/cm³ to about 1.5 g/cm³.

Crush strength values for the substantially spherical particulates ofthe present disclosure may be determined using ISO 13503-2, whichprovides a weight percentage of fines formed at a given stress level. Inparticular embodiments, no fines may be formed from certainsubstantially spherical particulates disclosed herein at stress levelsup to about 5000 psi.

Polyaromatic hydrocarbons suitable for forming the crosslinked reactionproducts of the present disclosure may be obtained from any source andhave any molecular structure, provided to that the molecular structureis capable of forming substantially spherical particulates followingcrosslinking. The polyaromatic hydrocarbons may comprise only carbon andhydrogen, or optional heteroatoms may be present in some embodiments.Heteroatoms such as nitrogen or sulfur, for example, may replace one ormore ring carbon atoms defining a portion of the polyaromatichydrocarbons suitable for use in the disclosure herein.

Additionally, in some embodiments, suitable polyaromatic hydrocarbonsmay be further oxidized either before or after undergoing crosslinkingaccording to the disclosure herein. Thus, in some embodiments, thecrosslinked reaction products of the present disclosure may comprise oneor more oxidized aromatic rings. Oxidized variants of suitablepolyaromatic hydrocarbons or crosslinked forms thereof may bear anoxygen atom upon an aromatic ring carbon atom (e.g., as a catechol,quinone or epoxide), or ring opening to a dicarboxylic acid may occur insome instances. Polyaromatic hydrocarbons bearing a heteroatom,particularly sulfur, may be oxidized upon the heteroatom (e.g., as asulfoxide, sulfone or sulfonic acid). Reagents such as hydrogen peroxideor sulfuric acid, for example, may promote the oxidation reaction.

Particularly suitable polyaromatic hydrocarbons for forming thecrosslinked reaction products of the present disclosure may be obtainedfrom various refinery process streams that otherwise have low intrinsicvalue, oftentimes a waste stream. By forming a crosslinked reactionproduct according to the disclosure herein, a considerably more valuableand useful material may be obtained. In illustrative embodiments,refinery process streams containing polyaromatic hydrocarbons suitablefor use in the disclosure herein may include, for example, steam crackertar, main column bottoms, vacuum residue, C5 rock, C3-C5 rock, slurryoil, asphaltenes, bitumen, K-pot bottoms, lube extracts, and anycombination thereof. These terms will be familiar to one having ordinaryskill in the art. Particular discussion regarding these refinery processstreams is provided hereinafter.

Steam cracker tar (also referred to as steam cracked tar or pyrolysisfuel oil) may comprise a suitable source of polyaromatic hydrocarbons insome embodiments of the present disclosure. “Steam cracker tar” is thehigh molecular weight material obtained following pyrolysis of ahydrocarbon feedstock into olefins, as described, for example, in U.S.Pat. No. 8,709,233, which is incorporated herein by reference. Suitablesteam cracker tar may or may not have had asphaltenes removed therefrom.Steam cracker tar may be obtained from the first fractionator downstreamfrom a steam cracker (pyrolysis furnace) as the bottoms product of thefractionator, nominally having a boiling point of 550° F. or above (288°C. or above) and higher. In particular embodiments, steam cracker tarmay be obtained from a pyrolysis furnace producing a vapor phaseincluding ethylene, propylene, and butenes; a liquid phase separated asan overhead phase in a primary fractionation step comprising C₅₊ speciesincluding a naphtha fraction (e.g., C₅-C₁₀ species) and a steam crackedgas oil fraction (primarily C₁₀-C₁₅/C₁₇ species having an initialboiling range of about 400° F. to 550° F.); and a bottoms fractioncomprising steam cracker tar having a boiling point range above about550° F. and comprising C₁₅/C₁₇₊ species.

Main column bottoms (also referred to as FCC main column bottoms orslurry oil) may comprise a suitable source of polyaromatic hydrocarbonsin some embodiments of the present disclosure. Typical polyaromatichydrocarbons that may be present in main column bottoms include thosehaving molecular weights ranging from about 250 to about 1000. Three toeight fused aromatic rings may be present in some instances.Polyaromatic hydrocarbons that may be present in main column bottomsinclude, but are not limited to, those shown in Formulas 10-21 below.

Suitable main column bottoms may or may not have had asphaltenes removedtherefrom. Residual cracking catalyst not removed cyclonically followingcracking may or may not remain present in the main column bottoms. Bothcatalyst-containing and catalyst-free main column bottoms may besuitable for use in the present disclosure.

Vacuum residue may comprise a suitable source of polyaromatichydrocarbons in some embodiments of the present disclosure. Like itsname suggests, “vacuum residue” is the residual material obtained from adistillation tower following vacuum distillation. Vacuum residue mayhave a nominal boiling point range of about 600° C. or higher.

C3 rock or C3-C5 rock may comprise a suitable source of polyaromatichydrocarbons in some embodiments of the present disclosure. C3-C5 rockrefers to asphaltenes that have been further treated with propane,butanes and pentanes in a deasphalting unit. Likewise, C3 rock refers toasphaltenes that have been further treated with propane. C3 and C3-C5rock may be high in metals like Ni and V and may contain high amounts ofN and S heteroatoms in heteroaromatic rings.

Bitumen or asphaltenes may comprise a suitable source of polyaromatichydrocarbons in some embodiments of the present disclosure. Some sourcesconsider bitumen and asphaltenes to be synonymous with one another. Ingeneral, asphaltenes refer to a solubility class of materials thatprecipitate or separate from an oil when in contact with paraffins(e.g., propane, butane, pentane, hexane or heptane). Bitumentraditionally refers to a material obtained from oil sands andrepresents a full-range, higher-boiling material than raw petroleum.

In addition to the crosslinked reaction product, various additives mayfurther be combined therewith to alter the resulting properties of thesubstantially spherical particulates. Suitable additives may include,for example, plasticizers, polymers, oils, fillers, and the like.

The substantially spherical particulates described hereinabove may bereadily prepared under acid-catalyzed conditions in an aqueous orsubstantially aqueous solvent in the presence of a surfactant. Thesurfactant promotes dispersion of the polyaromatic hydrocarbon, therebyallowing small droplets of the polyaromatic hydrocarbon to undergointerfacial crosslinking in the solvent. The surface tension of thewater thereby encourages formation of substantially sphericalparticulates, which eventually precipitate from the solvent once thesurfactant is no longer capable of promoting dispersion (e.g., once acritical particle size has been reached).

Accordingly, methods for synthesizing substantially sphericalparticulates of the present disclosure may comprise: reacting apolyaromatic hydrocarbon with a crosslinking agent in the presence of anacid catalyst and a surfactant in an aqueous solvent, and formingsubstantially spherical particulates in situ in the aqueous solvent inthe presence of the surfactant. The substantially spherical particulatescomprise a crosslinked reaction product of the polyaromatic hydrocarbonand the crosslinking agent, wherein the crosslinked reaction product isdescribed in further detail hereinabove.

Temperature conditions suitable for forming the crosslinked reactionproducts of the present disclosure may vary over a wide range. Ingeneral, any reaction temperature may be used at which the aqueoussolvent remains a liquid. For example, in some embodiments, the reactiontemperature may range from about −10° C. to about 100° C., or 0° C. toabout 90° C. Reactions under pressurized conditions are also possible,in which case the reaction temperature may be up to about 370° C., forexample, in a range from about 100° C. to about 200° C.

Any of the crosslinking agents discussed above may be used to form acrosslinked reaction product of the present disclosure in the presenceof a surfactant. Similarly, any polyaromatic hydrocarbon capable ofreacting with a crosslinking agent to form substantially sphericalparticulates may be utilized in the disclosure herein.

As referenced above, the size of the substantially sphericalparticulates described herein may be adjusted by a number of factorsincluding, for example, the concentration and type of surfactant usedwhen forming the crosslinked reaction product. Namely, the concentrationand type of surfactant may be chosen such that the crosslinked reactionproduct remains dispersed in the aqueous solvent until a criticalparticle size is reached, at which point precipitation of thesubstantially spherical particulates occurs. Thus, suitable surfactantsthereof are not believed to be particularly limited, provided that thesurfactant is capable of dispersing the polyaromatic hydrocarbon andpromoting a reaction between the polyaromatic hydrocarbon and thecrosslinking agent to yield a desired particle size. Suitablesurfactants may include cationic surfactants, anionic surfactants,neutral surfactants, zwitterionic surfactants, and any combinationthereof. Particular examples of suitable surfactants may include, forexample, dodecyltrimethylammonium bromide and 4-dodecylbenzenesulfonicacid.

Likewise, the concentration of the surfactant in the aqueous solvent maybe varied over a range of values in response to the size of thesubstantially spherical particulates to be produced. In variousembodiments, a concentration of the surfactant in the aqueous solventmay range from about 0.1 to about 10% (w/v) or about 0.5 to about 10%(w/v). In some or other embodiments, a concentration of the surfactantmay range from 1×10⁻³ M to about 10⁻⁵ M. Concentrations in the latterrange may be particularly effective for promoting micelle formation.

Polyaromatic hydrocarbons suitable for use in forming the substantiallyspherical particulates of the present disclosure is not believed to beparticularly limited. Particular examples of suitable polyaromatichydrocarbons may include one or more of the refinery process streamsdescribed hereinabove. In particular embodiments, suitable polyaromatichydrocarbons may have a boiling point of about 800° F. or higher. Insome or other particular embodiments, suitable polyaromatic hydrocarbonsmay have a hydrogen content of about 4% to about 20% on a mass basis.

The concentration of the polyaromatic hydrocarbon in the aqueous solventmay range from about 0.1% to about 90% (w/v) or about 1% to about 50%(w/v), or about 2% to about 15%.

Crosslinking agents suitable for use in forming the substantiallyspherical particulates of the present disclosure are likewise notbelieved to be particularly limited, provided that the crosslinkingagents are reactive with an aromatic ring in an aqueous solvent in somemanner. Particular examples of suitable crosslinking agents may includeany of the crosslinking agents described above, which may undergo areaction under acid-catalyzed conditions with an aromatic ring.

Depending on the desired particle size and/or the crosslink density ofthe substantially spherical particulates, the concentration of thecrosslinking agent in the aqueous solvent may vary over a considerablerange. In some embodiments, the crosslinking agent may be present in anamount ranging from about 0.1% to about 100% w/w of a total weight ofthe polyaromatic hydrocarbon. In more particular embodiments, thecrosslinking agent may be present in an amount ranging from about 20% toabout 100% w/w of a total weight of the polyaromatic hydrocarbons, orabout 20% to about 90% w/w, or about 20% to about 80% w/w, or about 20%to about 70% w/w, or about 20% to about 65% w/w, or about 20% to about50% w/w, or about 20% to about 40% w/w, or about 20% to about 30% w/w,or about 30% to about 90% w/w, or about 30% to about 80% w/w, or about30% to about 70% w/w, or about 30% to about 60% w/w, or about 30% toabout 50% w/w, or about 30% to about 40% w/w, or about 40% to about 90%w/w, or about 40% to about 80% w/w, or about 40% to about 70% w/w, orabout 40% to about 60% w/w, or about 40% to about 50% w/w, or about 50%to about 90% w/w, or about 50% to about 80% w/w, or about 50% to about70% w/w, or about 50% to about 60% w/w, or about 60% to about 90% w/w,or about 60% to about 80% w/w, or about 60% to about 70% w/w, or about70% to about 90% w/w, or about 70% to about 80% w/w, or about 80% toabout 90% w/w.

Acid catalysts suitable for promoting a reaction between a polyaromatichydrocarbon and a crosslinking agent according to the present disclosuremay vary as well. Suitable acid catalysts may include, for example,mineral acids, organic acids, supported acids, Lewis acids, and thelike. Particular examples of suitable acid catalysts may include, forexample, trimethylaluminum, aluminum chloride, zinc chloride, ferricchloride, methanesulfonic acid, trifluoromethanesulfonic acid,trichloroacetic acid, p-toluenesulfonic acid, phosphoric acid,polyphosphoric acid, tungstic acid, phosphotungstic acid,polyoxometalates, naphthalenesulfonic acid, benzenesulfonic acid,sulfuric acid, hydrochloric acid, hydrobromic acid, biphenylsulfonicacid, benzenetrisulfonic acid, and the like. Combinations of Lewis acidsand protic (Brönsted) acids may be used in some instances.

The concentration of the acid catalyst in the aqueous solvent may rangefrom about 1% to about 50% (w/v). In some or other embodiments, anamount of the acid catalyst may range from about 0.1% to about 50% w/wof the total weight of the crosslinking agent and the polyaromatichydrocarbon, or about 0.1% to about 40% w/w, or about 0.1% to about 40%,or about 0.1% to about 30%, or about 0.1% to about 20%, or about 0.1% toabout 10%, or about 0.5% to about 40%, or about 0.5% to about 30%, orabout 0.5% to about 20%, or about 0.5% to about 10%, or about 1% toabout 40%, or about 1% to about 30%, or about 1% to about 20%, or about1% to about 10% w/w.

In certain embodiments, the reactive functional group of thecrosslinking agent and an acid group for promoting functionalization ofthe polyaromatic hydrocarbon may be present in the same molecule. Forexample, in some embodiments, crosslinking agents containing a suitableacid group may be polymeric, such as the illustrative polymericcrosslinking agents shown in Formulas 22 and 23,

wherein A is a suitable acid group such as a sulfonic acid, phosphonicacid, or carboxylic acid.

In still other embodiments, the present disclosure provides fracturingmethods utilizing the substantially spherical particulates disclosedhereinabove. The substantially spherical particulates may function asproppants when employed in a fracturing operation, as describedhereinafter.

In various embodiments, fracturing methods of the present disclosure maycomprise: providing a plurality of proppant particulates comprising acrosslinked reaction product of a polyaromatic hydrocarbon and acrosslinking agent, in which the reaction product is formed assubstantially spherical particulates; introducing a fracturing fluidcomprising the plurality of proppant particulates into a subterraneanformation; and depositing at least a portion of the plurality ofproppant particulates within one or more fractures in the subterraneanformation. Any of the substantially spherical particulates describedhereinabove may be utilized in the fracturing methods discussed below.

Further embodiments of the fracturing methods may comprise combining theplurality of proppant particulates with a suitable carrier fluid totransport the proppant particulates into a desired location in thesubterranean formation. The carrier fluid may comprise an aqueous fluid,according to various embodiments of the present disclosure. In otherillustrative embodiments, the plurality of proppant particulates may becombined in a separate fluid that is subsequently injected into thefracturing fluid, possibly on-the-fly, as the fracturing fluid is beingpumped into the subterranean formation.

In more specific embodiments, the fracturing fluid may be introduced tothe subterranean formation at a pressure sufficient to create or extendat least one fracture within a matrix of the subterranean formation.Such pressures may be referred to as being above the fracture gradientpressure of the subterranean formation. One having ordinary skill in theart will be able to determine a suitable pressure for introducing afracturing fluid of the present disclosure in order to realize thebenefits and advantages described herein.

In other embodiments, a pad fluid lacking the proppant particulates maybe introduced initially to the subterranean formation at or above thefracture gradient pressure. Thereafter, once a plurality of fractureshas been created or extended, the proppant particulates may beintroduced to the subterranean formation to prevent the fractures fromclosing following a release of the hydraulic pressure.

In some embodiments, the plurality of proppant particulates may besynthesized prior to formulating the fracturing fluid. That is, theproppant particulates may be synthesized as described in further detailherein and then undergo combination with the fracturing fluid. Theproppant particulates may be present in any suitable amount in thefracturing fluid to promote a particular fracturing operation.

In other embodiments, methods of the present disclosure may furthercomprise forming the plurality of proppant particulates in situ withinthe fracturing fluid. More specifically, in such embodiments, thefracturing fluid may be an aqueous fracturing fluid comprising apolyaromatic hydrocarbon, a crosslinking agent, an acid catalyst, and asurfactant, suitable examples and amounts of which are described indetail hereinabove. Amounts and types of each of these components may bechosen such that the proppant particulates are formed in situ in adesired location within the subterranean formation.

Fracturing fluids of the present disclosure may be gelled or ungelled,depending on particular application needs. Advantageously, since thecrosslinked reaction products of the present disclosure exhibitrelatively low density values, gelling of the carrier fluid may not beneeded to promote particulate transport. Similarly, when the proppantparticulates are formed in situ, gelling of the fracturing fluid may beunnecessary.

The types of subterranean formations that may undergo fracturingaccording to the disclosure herein are not believed to be particularlylimited. Particular examples of subterranean formations that may undergofracturing according to the present disclosure include, for example,shale formations, oil sands, gas sands, and the like

in addition, certain fracturing fluids suitable for use in thedisclosure herein may contain one or more additives such as, forexample, salts, weighting agents, inert solids, fluid loss controlagents, emulsifiers, dispersion aids, corrosion inhibitors, emulsionthinners, emulsion thickeners, viscosifying agents, particulates, lostcirculation materials, foaming agents, gases, pH control additives,buffers, breakers, biocides, crosslinkers, stabilizers, chelatingagents, scale inhibitors, mutual solvents, oxidizers, reducers, frictionreducers, clay stabilizing agents, and any combination thereof. Onehaving ordinary skill in the art will be familiar with such additivesand amount thereof to use in a given fracturing fluid.

Embodiments disclosed herein include:

A. Solids compositions comprising substantially spherical particulates.The compositions comprise: a crosslinked reaction product of apolyaromatic hydrocarbon and a crosslinking agent, the crosslinkingagent comprising at least two functional groups that are reactive underacid-catalyzed conditions with an aromatic ring of the polyaromatichydrocarbon; wherein the crosslinked reaction product is formed assubstantially spherical particulates.

B. Methods for forming substantially spherical particulates. The methodscomprise: reacting a polyaromatic hydrocarbon with a crosslinking agentin the presence of an acid catalyst and a surfactant in an aqueoussolvent; and forming substantially spherical particulates in situ in theaqueous solvent, the substantially spherical particulates comprising acrosslinked reaction product of the polyaromatic hydrocarbon and thecrosslinking agent.

C. Methods for fracturing a subterranean formation. The methodscomprise: providing a plurality of proppant particulates comprising acrosslinked reaction product of a polyaromatic hydrocarbon and acrosslinking agent, the crosslinked reaction product being formed assubstantially spherical particulates; introducing a fracturing fluidcomprising the plurality of proppant particulates into a subterraneanformation; and depositing at least a portion of the plurality ofproppant particulates within one or more fractures in the subterraneanformation.

Embodiments A-C may have one or more of the following additionalelements in any combination:

Element 1: wherein the substantially spherical particulates have aparticle size ranging from about 10 microns to about 3 mm.

Element 2: wherein the at least two functional groups are located uponone or more aromatic rings of the crosslinking agent.

Element 3: wherein the at least two functional groups are independentlyselected from the group consisting of —CHO, —CHCH₂, —CH₂X, —C(═O)Y, andany combination thereof; wherein X is selected from the group consistingof halide, OH, and sulfonate; and wherein Y is selected from the groupconsisting of OH, Cl, and O-acyl.

Element 4: wherein the crosslinking agent is a polymeric crosslinkingagent.

Element 5: wherein the polyaromatic hydrocarbon is obtained from arefinery process stream.

Element 6: wherein the refinery process stream is selected from thegroup consisting of steam cracked tar, main column bottoms, vacuumresidue, C5 rock, C3-C5 rock, asphaltenes, bitumen, K-pot bottoms, lubeextracts, and any combination thereof.

Element 7: wherein the crosslinked reaction product comprises one ormore oxidized aromatic rings.

Element 8: wherein the fracturing fluid is introduced into thesubterranean formation at or above a fracture gradient pressure of thesubterranean formation.

Element 9: wherein the method further comprises: forming the pluralityof proppant particulates in situ within the fracturing fluid; whereinthe fracturing fluid is an aqueous fracturing fluid comprising thepolyaromatic hydrocarbon, the crosslinking agent, an acid catalyst, anda surfactant.

Element 10: wherein the crosslinking agent comprises at least twofunctional groups that are reactive under acid-catalyzed conditions withan aromatic ring of the polyaromatic hydrocarbon.

By way of non-limiting example, exemplary combinations applicable to A,B and C include: 1 and 2; 1-3, 1 and 4; 1 and 5; 1, 5 and 6; 1 and 7; 2and 3; 2 and 4; 2 and 5; 2, 5 and 6; 2 and 7; 3 and 5; 3, 5 and 6; 3 and7; 4 and 5; 4, 5 and 6; 4 and 7; 5 and 7; and 5, 6 and 7. Optionally,embodiment C may further include the following exemplary combinations,either alone or in further combination with any one or more of elements1-10: 8 and 9, 8 and 10; 9 and 10; and 8-10.

To facilitate a better understanding of the embodiments describedherein, the following examples of various representative embodiments aregiven. In no way should the following examples be read to limit, or todefine, the scope of the present disclosure.

EXAMPLES

Example 1: A reaction mixture was formed by combining 1 g of Aromatic200 (ExxonMobil Chemical Company, a mixture of C9-C15 aromatichydrocarbons) and 5 g of divinylbenzene in 10 g of water containing 1wt. % surfactant and 5 wt. % bismuth triflate catalyst. The reactionmixture was stirred continuously and allowed to react at 90° C.overnight. The resulting product was yellowish and formed sphericalparticulates in the millimeter size range. Some particulateagglomeration occurred during the reaction.

Example 2: A reaction mixture was formed by combining 1 g of Aromatic200 (ExxonMobil Chemical Company, a mixture of C9-C15 aromatichydrocarbons) and 5 g of divinylbenzene in 20 g of water containing 5wt. % 4-dodecylbenzenesulfonic acid surfactant and 20 mg Yb(OTf)₃catalyst. The reaction mixture was stirred continuously at 300 rpm andallowed to react at 90° C. overnight. The resulting product wasyellowish and formed spherical particulates in the millimeter sizerange. Some particulate agglomeration occurred during the reaction.

All documents described herein are incorporated by reference herein forpurposes of all jurisdictions where such practice is allowed, includingany priority documents and/or testing procedures to the extent they arenot inconsistent with this text. As is apparent from the foregoinggeneral description and the specific embodiments, while forms of thedisclosure have been illustrated and described, various modificationscan be made without departing from the spirit and scope of thedisclosure. Accordingly, it is not intended that the disclosure belimited thereby. For example, the compositions described herein may befree of any component, or composition not expressly recited or disclosedherein. Any method may lack any step not recited or disclosed herein.Likewise, the term “comprising” is considered synonymous with the term“including.” Whenever a method, composition, element or group ofelements is preceded with the transitional phrase “comprising,” it isunderstood that we also contemplate the same composition or group ofelements with transitional phrases “consisting essentially of,”“consisting of,” “selected from the group of consisting of,” or “is”preceding the recitation of the composition, element, or elements andvice versa.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the present specification and associated claims areto be understood as being modified in all instances by the term “about.”Accordingly, unless indicated to the contrary, the numerical parametersset forth in the following specification and attached claims areapproximations that may vary depending upon the desired propertiessought to be obtained by the embodiments of the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claim, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Whenever a numerical range with a lower limit and an upper limit isdisclosed, any number and any included range falling within the range isspecifically disclosed. In particular, every range of values (of theform, “from about a to about b,” or, equivalently, “from approximately ato b,” or, equivalently, “from approximately a-b”) disclosed herein isto be understood to set forth every number and range encompassed withinthe broader range of values. Also, the terms in the claims have theirplain, ordinary meaning unless otherwise explicitly and clearly definedby the patentee. Moreover, the indefinite articles “a” or “an,” as usedin the claims, are defined herein to mean one or more than one of theelement that it introduces.

One or more illustrative embodiments are presented herein. Not allfeatures of a physical implementation are described or shown in thisapplication for the sake of clarity. It is understood that in thedevelopment of a physical embodiment of the present disclosure, numerousimplementation-specific decisions must be made to achieve thedeveloper's goals, such as compliance with system-related,business-related, government-related and other constraints, which varyby implementation and from time to time. While a developer's effortsmight be time-consuming, such efforts would be, nevertheless, a routineundertaking for one of ordinary skill in the art and having benefit ofthis disclosure.

Therefore, the present disclosure is well adapted to attain the ends andadvantages mentioned as well as those that are inherent therein. Theparticular embodiments disclosed above are illustrative only, as thepresent disclosure may be modified and practiced in different butequivalent manners apparent to one having ordinary skill in the art andhaving the benefit of the teachings herein. Furthermore, no limitationsare intended to the details of construction or design herein shown,other than as described in the claims below. It is therefore evidentthat the particular illustrative embodiments disclosed above may bealtered, combined, or modified and all such variations are consideredwithin the scope and spirit of the present disclosure. The embodimentsillustratively disclosed herein suitably may be practiced in the absenceof any element that is not specifically disclosed herein and/or anyoptional element disclosed herein.

The invention claimed is:
 1. A solid composition comprising:substantially spherical particulates, the substantially sphericalparticulates each comprising at least one polymer having at least oneC9-C15 aromatic hydrocarbon unit and at least one crosslinking grouphaving a phenyl group and two C2 groups bonded to the phenyl group,wherein the at least one C9-C15 aromatic hydrocarbon unit and the atleast one crosslinking group are crosslinked by a C2 group of the two C2groups bonded directly to an aromatic ring of the at least one C9-C15aromatic hydrocarbon unit and bonded directly to the phenyl group of thecrosslinker unit crosslinking group.
 2. The solid composition of claim1, wherein the substantially spherical particulates have a particle sizeranging from about 10 microns to about 3 mm.
 3. The solid composition ofclaim 1, wherein C9-C15 aromatic hydrocarbon used to form the at leastone C9-C15 aromatic hydrocarbon unit is obtained from a refinery processstream.
 4. The solid composition of claim 3, wherein the refineryprocess stream is selected from the group consisting of steam crackedtar, main column bottoms, vacuum residue, asphaltenes, bitumen, lubeextracts, and any combination thereof.
 5. The solid composition of claim1, wherein the polymer comprises one or more oxidized aromatic rings. 6.The solid composition of claim 5, wherein the one or more oxidizedaromatic rings are selected from the group consisting of catechol,quinone, epoxide substituted aromatic ring, and combinations thereof. 7.The solid composition of claim 1, wherein the at least one polymer has aplurality of C9-C15 aromatic hydrocarbon units and a plurality ofcrosslinking groups, each of the crosslinking groups having a phenylgroup and two C2 groups bonded to the phenyl group, wherein each of theC9-C15 aromatic hydrocarbon units is crosslinked to an aromatichydrocarbon crosslinking group of the plurality of crosslinking groupsby a C2 group of the two C2 groups, the C2 group bonded directly to anaromatic ring of a C9-C15 aromatic hydrocarbon unit of the plurality ofthe C9-C15 aromatic hydrocarbon units and bonded directly to a phenylgroup of a crosslinking group of the plurality of crosslinking groups.8. The solid composition of claim 7, wherein the C9-C15 aromatichydrocarbon units are independently selected from the group consistingof anthracene, indane, indene, tetralin, and combinations thereof. 9.The solid composition of claim 7, wherein the C9-C15 aromatichydrocarbon units are unsubstituted C9-C15 aromatic hydrocarbon units.10. The solid composition of claim 7, wherein each of the phenyl ringsof the crosslinking groups is ortho substituted with: a first C2 groupof the two C2 groups, and a second C2 group of the two C2 groups. 11.The solid composition of claim 7, wherein each of the phenyl rings ofthe crosslinking groups is meta substituted with: a first C2 group ofthe two C2 groups, and a second C2 group of the two C2 groups.
 12. Thesolid composition of claim 7, wherein each of the phenyl rings of thecrosslinking groups is para substituted with: a first C2 group of thetwo C2 groups, and a second C2 group of the two C2 groups.
 13. The solidcomposition of claim 7, wherein each of the substantially sphericalparticulates has about zero weight percent of fines at a stress level upto 5,000 psi in accordance with ISO 13503-2.
 14. The solid compositionof claim 1, wherein the C2 group is formed from CHCH₂.
 15. A solidcomposition comprising: substantially spherical particulates, thesubstantially spherical particulates each having a particle size ofabout 100 microns to about 1 mm and comprising at least one polymerhaving at least one C9-C15 aromatic hydrocarbon unit and at least onecrosslinker unit crosslinking group having a phenyl group and two C2groups bonded to the phenyl group, wherein: the at least one C9-C15aromatic hydrocarbon unit and the at least one crosslinking group arecrosslinked by a C2 group of the two C2 groups, the C2 group bondeddirectly to an aromatic ring of the at least one C9-C15 aromatichydrocarbon unit and bonded directly to the phenyl group of the at leastone crosslinker unit crosslinking group.
 16. The solid composition ofclaim 15, wherein the at least one polymer has a plurality of C9-C15aromatic hydrocarbon units and a plurality of crosslinking groups, eachof the crosslinking groups having a phenyl group and two C2 groupsbonded to the phenyl group, wherein: each of the C9-C15 aromatichydrocarbon units is crosslinked to a crosslinking group of theplurality of aromatic hydrocarbon crosslinking groups by a C2 group ofthe two C2 groups, the C2 group bonded directly to an aromatic ring of aC9-C15 aromatic hydrocarbon unit of the plurality of the C9-C15 aromatichydrocarbon units and bonded directly to a phenyl group of acrosslinking group of the plurality of crosslinking groups.
 17. Thesolid composition of claim 16, wherein each of the C9-C15 aromatichydrocarbon units are unsubstituted.
 18. The solid composition of claim16, wherein the phenyl group of each of the crosslinking groups isunsubstituted.
 19. The solid composition of claim 16, wherein each ofthe C2 groups is formed from CHCH₂.